Separable fastener



Feb. 26, 1935. r M'JBACR 1,992,253

SEPARABLE-FASTENER Ori inal FiIed Dec. 14, 1929 n? /a 0 49 /a I N V EN TOR.

/zwa ATTOR Y Patented ,Feb. 26, 1935 UNITED STATES PATENT OFFICE" SEPARABLE FASTENER Application 8 Claims.

My invention relates to fastening devices and particularly to that class of such devices which comprises opposed series of fastener elements adapted to be brought together at an angle and progressively interlocked.

Fastening devices of this type have been manufactured in various forms, the most successful of which has been those which employ interlocking elements disposed in staggered relation on a pair of-stringers, such elements having portions at one end to clamp them to a tape and at the other end a projection and recess on opposite sides of the element to interlock with projections and recesses of elements on the other stringer. These projections and recesses have always been formed in a single operation by means of a punch entering the metal to form the recess and displacing metal which is forced down into a die to form the projection. In fastener elements of this type the shape of the projection has always been practically the same as the recess.

With the fastener elements of my invention the recess and projection may be formed by two entirely separate operations. The shape and size of the projection can in this way be controlled independently of the recess.

In another of its aspects'my invention par;- ticularly relates to an improved construction of a fastener element made from. a bent wire.

It has heretofore been proposed to bend a round wire to substantially a U-shape and then form interlocking projections at the bend and.

later clamp the elements to a fabric stringer. A fastener of this type as well as a method and machine for making it is disclosed in my Patent No. 1,653,320 December 20, 1927. In this patent as well as in other forms of wire fastener elements heretofore devised, the interlocking projection was formed by deforming material from the inner side of the bend in an outer direction. It will be seen that it is inherent in this type of a fastener element that the amount of metal at the bend in the wire is definitely limited. It is also a well known fact that the strength of a fastener of this type is limited to its power of holding itself to the corded edge of a fabric stringer. With the wire fastener element the holding power depends upon the cross-section of the wire at the bend for this is its weakest section. Thus, the material being displaced from 'the inner side of the bend is taken away from the point where it is needed for strength of the fastener. Although a fastener made in this manner may be sufliciently strong for many uses there are other uses where. increased strength is desirable. It is ac- December 14, 1929, Serial No. 414,156 Renewed August 9, 1933 cordingly one of the main objects of my invention to provide improvedwire fastener elements in which the material to form the projection is displaced from parts of the wire other than the inner side of the bend.

A more specific object of my invention is to provide an improved bent wire fastener element having a recess on one side formed wholly in the bent section of the wire.

Still another object of my invention is to pro- 10 vide an improved fastenerelement in which an interlocking projection consists ofmaterial deformed or scraped up from an outer surface of the wire.

A further object is to provide a fastener made 15 of improved bent wire elements which shall be extremely flexible.

Otherobjects and advantages of the invention will more fully appear during the course of the following specification. 20

In the accompanying drawing, I have shown for, purposes of illustration one embodiment which my invention may assume in practice. In the drawing:

Fig. 1 is a plan view of a fastener constructed 25 according to my invention with a part of the slider shown in section to illustrate the interlock ing principle.

Fig. 2 is a perspective view illustrating a method of forming the recess in a fastener element show- 30 ingportions of the tools employed.

Fig. 3 is an elevation view illustrating a method of forming the interlocking projections showing g portions of the tools.

Figs. 4 and 5 are views of a wire blank used in 35 making the fastener elements of my invention.

Fig. 6 is a transverse sectional view illustrating a fastener in an intermediate step of production.

Fig. 'l is an elevation view illustrating the stringeriin the same stage as shown in Fig. 6.-

Fig. 8 is a sectional view of a single fastener element attached to its stringer.

Figs. 9 and 10 are other views of a single fastener element.

Fastening devices of the type to which my 45 invention relates each usually comprises a pair of flexible stringers which in the drawing are designated 9 and a series of spaced fastener elements secured to the adjacent ed es of said stringers. A slider 10 is almost always employed to bring the fastener elements together successively at an angle to each other to interlock the fas tener elements progressively. -The slider illustrated comprisesa pair of overlying spaced wings positioned on opposite sides of the stringers and has a Y-shaped channel through which the fastener elements pass during travel of the slider. The spaced wings are connected by an integral wedging portion 11 and a pull member 12 is suitably connected to one of the slider wings in a manner not shown. Each of the fastener stringers is provided with a corded edge 13 which is preferably made by sewing twisted cords on opposite sides of a tape and along one of its longitudinal edges.

The fastener elements 14 are alike on both stringers and a description of the construction of one of the elements will be sufiicient. Each element comprises a bent wire having spaced side portions 14 and 15 on opposite sides of the corded edge and forming the clamping jaws. The side portions are joined by an integral connecting portion 16 at the bend in the wire and on opposite sides (if this connecting portion are formed an interlocking recess 17 and a projection 18. It will be noted that the recess 17 is formed wholly within the bent section 16 of the wire and opens only in the upward direction. A substantially flat guiding face 19 extends across the front of thefastener and serves to guide the fastener elements one upon the other in interlocking. In order to make the fastener extremely flexible the bent section of each of the fastener elements is narrowed down on the projection side of the elements by formation of the indentations 160;. This allows one element to rock freely on another when the fastener is flexed without affecting the interlocking function.

It will be noted that in forming the recess and projection which constitute the interlocking means of the fastener member, the wire is mere- 1y indented informing the recess and the material has a tendency to move toward the tape, while in forming the projection. the material is scraped up along the front face of the fastener member and likewise it tends to move inwardly toward the tape. It will be noted that this slight movement of material changes the form but not the cross-sectional area of the material at the bend. The area remains substantially uniform. To facilitate understanding of my invention a suitable method of making my improved fastener will be described. The novel aspects of this method will be set forth ,and claimed in a divisional or continuation application.

Referring to Figs. 4 and 5 a blank 20 is cut from a piece of wire and is formed with suitable means such as the indentations 21 adjacent the ends of the elements to engage the corded edge of the tape when the wireblank is clamped to the stringer. In this form the wire blanks may be tumbled to remove all burrs and hoppered by any suitable means such as described in my Patent No. 1,653,320 mentioned above. The indentations 21 need not be formed until some later point in the stage of production as described in my above mentioned patent.

The next step of the-method comprises bending the wire blanks around the corded edge of a stringer and thus securing them in place in properly spaced relation. This step is illustrated in Figs. 6 and 7. The final steps in the method are the forming of the interlocking projection and the forming of the recess either of which steps may precede the other. In Fig. 2 is illustrated the method of forming the recess wherein suitable side tools 22 and 23 operate in a lateral direction to successively engage and hold the fastener blanks as the stringer passes between the tools with an intermittent motion. The blank is sup ported on the tools 22 while the tools 23 are shaped to fit around and grip the blank while it is held between the side tools. These tools are also formed to produce .the indentations 16a and limit the width of the projection 18. The recess is formed by a suitable punch 24 having the desired forming point 25 which moves into the blank from an acute angle entering between a pair of adjacent blanks on the stringer. The mechanism for operating the tools and other parts of a machine especially adapted for the purpose, will not be illustrated and described in detail in this application and will be made the subject of another application.

The steps of forming the interlocking projection are illustrated in Fig. 3. A pair of suitable side operating tools 26 similar to the ones illustrated in Fig. 2, enter between the fastener blanks along the stringer and support each of the elements in turn while the projection is being formed. The tool for forming the projection is indicated at 27 and is provided with a suitable cutting edge which scrapes or punches up material from the front outer surface of each of the blanks so as to form the point or projection 18. This tool is also operated at an acute angle to the plane of the blanks.

It will be observed that no material is taken from the inner side of the bend in the wire blank and in fact, additional material is moved into this portion. This will be apparent in Fig. 8 where, in forming the recess 17, the material flows toward the space between side portions of the member to form a bulge as indicated at 28. An alloy of nickel, zinc and copper has been found very suitable for fasteners, and this material works very wellwith my improved method outlined above. It will also be observed that by forming the projection and recess in two independent operations, the shape and size of one is not controlled by the other.

While I have in this application specifically described one embodiment which my invention may assume in practice, it will be understood that this embodiment is merely for the purposes of illustration and description and that various forms may be devised within the scope of my invention as defined in the appended claims.

What I claim as my invention is:

1. A fastening device having opposed series of fastener elements adapted to be brought together and progressively interlocked, each of said elements of one series comprising a wire bent upon itself and having a recess at the bend which is indented in a single continuous body portion of said wire and adjacent the center line of such portion, the material throughout the bend having substantially uniform cross-sectional area, and means on the opposite series for interlocking with said recesses.

2. In a fastening device, a pair of fastener stringers, rows of cooperating fastener elements secured to said stringers, each of said elements being formed from a single piece of wire which is bent upon itself to provide clamping jaws for securing it to its stringer, and the bent portion projecting outwardly from the edge of the stringer and having interlocking means formed at the bend, the interlocking means being so formed that the material throughout said bend has substantially uniform cross-sectional area, said interlocking meanscomprising a recess on one side formed by displacing the material of said wire from the recess toward the clamping jaws.

3. In a fastening device, a pair of fastener stringers, rows of cooperating fastener elements secured to said stringers, each of said elements on one stringer comprising a wire bent upon itself and having interlocking means including a recess formed in the body portion of said wire at the bend opening only in one direction, the interlocking means being so formed that the material throughout the bend has substantially uniform cross-sectional area, and means on the opposite stringer for interlocking with said re- 4. In a fastening device, a pair of fastener stringers, rows of cooperating fastener elements secured to said stringers, each of said elements comprising a wire bent to substantially a U -shape, the spaced side portions of such U-shaped wire forming means for attaching it to its stringer, and interlocking means formed at the bend of said wire including a recess spaced from the space between said side portions of the U-shaped member, the interlocking means being so formed that the material throughout the bend has substantially uniform cross-sectional area.

5. In a fastening device, a pair of fastener stringers, rows of cooperating fastener elements secured to said stringers, each of said elements on one stringer comprising a substantially round wire bent upon itself to form side portions and an integral bent connecting portion, interlocking means formed wholly in said connecting portion comprising a recess on one side thereof and a projection on the other side to interlock with similar fastener elements on the opposite stringer, the interlocking means being so formed that the material throughout the bend has substantially uniform cross-sectional area.

6. In a fastening device of the class described, a pair of fastener stringers having rows of cooperating fastener elements on their adjacent edges, each of said elements being formed from a single piece of wire which is bent upon itself toprovide clamping jaws, interlocking means formed in the bent section, the outside surfaces of said wire adjacent the interlocking means having indentations formed therein for increasing the flexibility of the fastener, and a slider for controlling said fastener elements, the interlocking means being so formed that the material throughout the bend has substantially uniform cross-sectional area.

7; In a fastening device of the class described, a, pair of fastener stringers having rows of cooperating fastener elements arranged in staggered relation on their adjacent edges, each of said elements comprising a round wire bent to U-shape, the material throughout the bend having substantially uniform cross-sectional area, a recess formed at the bend on one side of the element, and a projection on the opposite side of the element, the outside surfaces of said wire on opposite sides of .said projection being indented to provide inclined surfaces for rocking on an adjacent fastener element, and a slider for bringing said fastener elements together and causing engagement of the projections and recesses of one series with the recesses and projections of the opposite series.

8. In a fastening device of the class described, a pair of fastener stringers having rows of cooperating fastener elements arranged in staggered relation on their adjacent edges, each of said elements comprising a round wire bent to U-shape, a recess formed out of the wire at the bend on one side of the element, and a projection on the opposite side of the element, the recess and projection being so formed that the material throughout the bend has substantially uniform cross-sectional area, the outside surfaces of said wire on opposite sides of said projection being g indented to provide inclined surfaces for rocking on an adjacent fastener element, and a slider for bringing said fastener elements together and causing engagment of the projections and recesses of one series with the recesses and projections of the opposite series.

GIDEON SUNDBACK. 

